expand: Ensure result is escaped in cvtnum

The minus sign generated from arithmetic expansion is currently
unquoted which causes anomalies when the result is used in where
the quoting matters.

This patch fixes it by explicitly calling memtodest on the result
in cvtnum.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 14 insertions, 13 deletions

diff --git a/src/expand.c b/src/expand.c
index c5ad37d..14daa63 100644
--- a/src/expand.c
+++ b/src/expand.c
@@ -116,7 +116,7 @@ static char *expari(char *start, int flag);
 STATIC void expbackq(union node *, int);
 STATIC char *evalvar(char *, int);
 static size_t strtodest(const char *p, int flags);
-static void memtodest(const char *p, size_t len, int flags);
+static size_t memtodest(const char *p, size_t len, int flags);
 STATIC ssize_t varvalue(char *, int, int, int);
 STATIC void expandmeta(struct strlist *, int);
 #ifdef HAVE_GLOB
@@ -133,7 +133,7 @@ STATIC int pmatch(const char *, const char *);
 #else
 #define pmatch(a, b) !fnmatch((a), (b), 0)
 #endif
-STATIC int cvtnum(intmax_t);
+static size_t cvtnum(intmax_t num, int flags);
 STATIC size_t esclen(const char *, const char *);
 STATIC char *scanleft(char *, char *, char *, char *, int, int);
 STATIC char *scanright(char *, char *, char *, char *, int, int);
@@ -463,7 +463,7 @@ static char *expari(char *start, int flag)
 	result = arith(start);
 	popstackmark(&sm);
 
-	len = cvtnum(result);
+	len = cvtnum(result, flag);
 
 	if (likely(!(flag & EXP_QUOTED)))
 		recordregion(begoff, begoff + len, 0);
@@ -746,7 +746,7 @@ again:
 	if (subtype == VSLENGTH) {
 		if (flag & EXP_DISCARD)
 			return p;
-		cvtnum(varlen > 0 ? varlen : 0);
+		cvtnum(varlen > 0 ? varlen : 0, flag);
 		goto record;
 	}
 
@@ -795,15 +795,17 @@ record:
  * Put a string on the stack.
  */
 
-static void memtodest(const char *p, size_t len, int flags)
+static size_t memtodest(const char *p, size_t len, int flags)
 {
 	const char *syntax = flags & EXP_QUOTED ? DQSYNTAX : BASESYNTAX;
 	char *q;
+	char *s;
 
 	if (unlikely(!len))
-		return;
+		return 0;
 
 	q = makestrspace(len * 2, expdest);
+	s = q;
 
 	do {
 		int c = (signed char)*p++;
@@ -818,6 +820,7 @@ static void memtodest(const char *p, size_t len, int flags)
 	} while (--len);
 
 	expdest = q;
+	return q - s;
 }
 
 
@@ -875,7 +878,7 @@ varvalue(char *name, int varflags, int flags, int quoted)
 		if (num == 0)
 			return -1;
 numvar:
-		len = cvtnum(num);
+		len = cvtnum(num, flags);
 		break;
 	case '-':
 		p = makestrspace(NOPTS, expdest);
@@ -1711,15 +1714,13 @@ casematch(union node *pattern, char *val)
  * Our own itoa().
  */
 
-STATIC int
-cvtnum(intmax_t num)
+static size_t cvtnum(intmax_t num, int flags)
 {
 	int len = max_int_length(sizeof(num));
+	char buf[len];
 
-	expdest = makestrspace(len, expdest);
-	len = fmtstr(expdest, len, "%" PRIdMAX, num);
-	STADJUST(len, expdest);
-	return len;
+	len = fmtstr(buf, len, "%" PRIdMAX, num);
+	return memtodest(buf, len, flags);
 }
 
 STATIC void